1. Field of the Invention
The invention relates to a tape cassette for use in an apparatus for recording and/or playing back magnetic registrations on a recording tape, which cassette has a casing comprising a bottom and cover wall as well as side walls, in which two winding hubs for winding and unwinding the tape respectively are provided, a corrugated film being located between the tape winding and the bottom and cover wall respectively.
2. Description of the Invention
A tape cassette of this type is known from U.S. Pat. No. 3,675,875. The material of which the corrugated film used in said known cassette is made is a synthetic material such as polyester, having a thickness of 12 to 50 .mu.m. The corrugated film has between about 2 to 20 corrugations per cm., the corrugation ratio ranging between the values 1.5 and 15, said corrugation ratio being defined as the ratio between the thickness of the corrugated film and the material thickness of the original film. It has been found that the spring constant of the known film, which is defined as the ratio of the force which is exerted on the film and the deflection of the film, is relatively high and that the film is consequently relatively stiff, so that the behaviour of said film does not differ appreciably from the conventional flat films. Especially when this magnetic tape is used -- in the order of 9 .mu.m -- problems will occur. The tape run in the cassette appears to be disturbed in that the tape is warped about its longitudinal axis and is trapped between the tape winding and film, so that the cassette can no longer be used. Another serious problem is jamming of the tape winding in the cassette due to the growing of the winding on the axial direction so-termed telescoping of the tape coil. In the event of telescoping the tape becomes jammed against the bottom or cover wall of the cassette, so that the winding friction of the apparatus is no longer capable of winding the tape any further. This gives rise to so-called tape spilling near the capstan of the apparatus, because the tape is still being transported by the capstan/pressure roller combination.